Tilt-preventing fan

ABSTRACT

The present invention provides a tilt-preventing fan having a blade device, a motor, a magnet device, a frame and a ball bearing. The blade device has a blade shaft. The blade shaft has an outer surface and a ring attached the outer surface. The motor is mounted around the blade shaft. The magnet device is mounted around the motor. The frame has a receiving device mounted in the central hole of the motor from the second opening and has an inner flange positioned around the blade shaft. The receiving device has a base, a resilient member and an abrasion-resistant pad abutting the blade shaft. The resilient member is mounted between the base and the abrasion-resistant pad. The ball bearing is mounted between the ring and inner flange. The ball bearing is firmly held between the ring and inner flange and capable of preventing the blade shaft from tilting.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tilt-preventing fan, especially to a fan that is capable of preventing tilt of a blade shaft.

2. Description of the Prior Art

With reference to FIG. 7, a first conventional tilt-preventing fan is used to drive fan blades and comprises a ball bearing (91) and a sleeve (92). The first conventional fan redundantly employs the ball bearing (91) and the sleeve (92) to hold a blade shaft (93) in order to prevent the blade shaft (93) from tilting. However, the life of a common ball bearing is approximately 50,000 hours while a common sleeve 25,000 hours. Thus the failure of the short-life sleeve (92) leads to the failure of the first conventional tilt-preventing fan despite the operable ball bearing (91).

With reference to FIG. 8, a second conventional tilt-preventing fan employs a first ball bearing (94) and a second ball bearing (95) to hold a blade shaft (96). Regarding the similar life length of the first ball bearing (94) and the second ball bearing (95), the second conventional tilt-preventing fan is expected to have longer life than the foregoing first conventional tilt-preventing fan. However, a ball bearing requires a considerably larger space than a sleeve, thus downsizing of the second conventional tilt-preventing fan is extremely difficult.

U.S. Pat. No. 5,982,064 discloses a third conventional tilt-preventing fan. With reference to FIGS. 7 and 8 of U.S. Pat. No. 5,982,064, the third conventional tilt-preventing fan comprises a blade shaft, a base, a frame, a disc, one ball bearing and a resilient member. The blade shaft comprises a first end and a second end. The base receives the second end of the blade shaft and comprises a blade-shaft-contacting surface contacting an end of the blade shaft. The frame holds the base and the blade shaft and comprises an inner flange. The inner flange positions around the blade shaft between the first end and the second end of the blade shaft. The disc is attached around the blade shaft between the second end of the blade shaft and the inner flange. The ball bearing is attached to the blade shaft, mounted between the inner flange and the disc and comprises an outer rail and an inner rail. The outer rail abuts against the inner flange. The resilient member is mounted between the inner rail and the disc.

The blade-shaft-contacting surface of the base recesses due to continuous drilling of the blade shaft. The recessing of the blade-shaft-contacting surface of the base allows the blade shaft, the disc, the ball bearing and the resilient member to move away from the inner flange of the frame. Especially when the blade-shaft-contacting surface of the base is facing upwards, gravity will draw the blade shaft, the disc, the ball bearing and the resilient member and keep the outer rail from contacting the inner flange. It is clear that when the blade-shaft-contacting surface of the base recesses, the inner flange and the disc will no longer be able to firmly hold the ball bearing and will allow the blade shaft to tilt with the ball bearing.

To overcome the shortcomings, the present invention provides a tilt-preventing fan to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the invention is to provide a tilt-preventing fan that is suitable for downsizing and has a long life.

The tilt-preventing fan in accordance with the present invention has a blade device, a motor, a magnet device, a frame and a ball bearing.

The blade device has a blade shaft and multiple blades radially attached to the blade shaft. The blade shaft has an outer surface and a ring attached the outer surface. The motor for rotating the blade shaft is mounted around the blade shaft. The magnet device providing a magnetic field for the motor is mounted around the motor. The frame has a receiving device mounted in the central hole of the motor from the second opening and has an inner flange positioned around the blade shaft. The receiving device has a base, a resilient member and an abrasion-resistant pad abutting the blade shaft. The resilient member is mounted between the base and the abrasion-resistant pad. The ball bearing is mounted between the ring and inner flange.

The resilient member allows the ring to push the ball bearing against the inner flange, thus the ball bearing is firmly held between the ring and inner flange and capable of preventing the blade shaft from tilting.

Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view of a first embodiment of a tilt-preventing fan in accordance with the present invention;

FIG. 2 is an exploded, sectional side view of the tilt-preventing fan in FIG. 1;

FIG. 3 is a sectional side view of a second embodiment of a tilt-preventing fan in accordance with the present invention;

FIG. 4 is an exploded side view of the tilt-preventing fan in FIG. 3;

FIG. 5 is a sectional side view of a third embodiment of a tilt-preventing fan in accordance with the present invention;

FIG. 6 is an exploded, sectional side view of the tilt-preventing fan in

FIG. 5;

FIG. 7 is a sectional side view of a first conventional tilt-preventing fan of the prior art; and

FIG. 8 is a sectional side view of a second conventional tilt-preventing fan of the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a first embodiment of tilt-preventing fan in accordance with the present invention has a blade device (10), a motor (20), a magnet device (30), a frame (40) and a ball bearing (50).

The blade device (10) comprises a blade shaft (11) and multiple blades (12). The blade shaft (11) comprises an outer surface, a first end (111), a second end (112), and a ring (113). The ring (113) is formed on the outer surface between the first end (111) and second end (112). Preferably, the ring (113) is formed near the second end (112). More preferably, the blade shaft (11) further comprises an annular slot (114) formed on the outer surface between the first end (111) and second end (112) and the ring (113) is mounted around the annular slot (114).

The blades (12) may be radially mounted between the first end (111) and the ring (113) or radially mounted to the first end (111). In the first embodiment, the blades are mounted to the first end (111).

The motor (20) for rotating the blade shaft (11) is mounted around the blade shaft (11) and comprises a central hole (21). The central hole (21) comprises an inner surface, a first opening (211) and a second opening (212).

The magnet device (30) is mounted around the motor (20) and provides a magnetic field allowing the motor (20) to operate with electric power.

The frame (40) holds the blade device (10), the motor (20) and the magnet device (30) and comprises a receiving device (41) and an inner flange (42). The receiving device is mounted into the central hole (21) of the motor (20) from the second opening (212) and comprises a base (411), a resilient member (412) and an abrasion-resistant pad (413).

The base (411) comprises a first surface (4111). The resilient member (412) is attached to the first surface (4111) of the base (411) and comprises a first end and a second end attached to the first surface (4111) of the base (411). In the first embodiment, the resilient member (412) is a spring. The abrasion-resistant pad (413) is attached to the first end of the resilient member (412) and abuts to the second end (112) of the blade shaft (11). The resilient member (412) pushes against the base (411) and the abrasion-resistant pad (413). Thus the abrasion-resistant pad (413) passively pushes at the second end (112) of the blade shaft (11) and moves the blade shaft (11) toward the direction point at the first end (111) of the blade shaft (11).

The inner flange (42) is positioned around the blade shaft (11) between the blades (12) and the ring (113). In the first embodiment, the inner flange (42) is attached to the inner surface of the central hole (21) between the first opening (211) and the second opening (212) of the central hole (21). Preferably, the inner flange (42) is attached to the inner surface of the central hole (21) near the first opening (211).

The ball bearing (50) holds the blade shaft (11) and is mounted between the ring (113) and the inner flange (42) and comprises an annular outer rail (51), an annular inner rail (52) and multiple balls (53). The outer rail (51) is pushed by the inner flange (42) towards the ring (113) and comprises a semicircular outer groove. The semicircular outer groove comprises a first outer portion and a second outer portion. The inner rail (52) is pushed by the ring (113) towards the inner flange (42) and comprises a semicircular inner groove. The semicircular inner groove comprises a first inner portion and a second inner portion. The balls (53) are movably mounted between the outer groove of the outer rail (51) and the inner groove of the inner rail (52).

Since the blade shaft (11) is pushed by the abrasion-resistant pad (413) driven by the resilient member (412), the ring (113) of the blade shaft (11) tends to move toward the first end (111) of the blade shaft (11). Thus the ring (113) pushes the inner rail (52) of the ball bearing (50) toward the same direction or towards the inner flange (42). From a reverse point of view, the inner flange (42) reacts against the pushing ring (113) and pushes the outer rail (51) of the ball bearing (50) towards the ring (113). The foregoing structure allows the ball bearing (50) to be firmly held between the inner flange (42) and the ring (113) and thus prevents both the ball bearing (50) and the blade shaft (11) held by the ball bearing (50) from tilting.

Even when the abrasion-resistant pad (413) recesses due to considerable drilling of the second end (112) of the blade shaft (11), the resilient member (413) keeps applying a force for moving the abrasion-resistant pad (413) towards the inner flange (42). With the foregoing structure, the constantly pushing resilient member (413) compensates the recessing of the abrasion-resistant pad (413) and allows the ball bearing (50) to be firmly held between the ring (113) and the inner flange (42).

When the motor (20) is supplied with electric power to drive the blade shaft (11) to rotate, the first outer portion of the outer groove of the outer rail (51) and the second portion of the inner groove of the inner rail (52) contact the balls (53) and allow the balls (53) to move therebetween.

With reference to FIGS. 3 and 4, a second embodiment of tilt-preventing fan in accordance with the present invention is similar to the aforementioned first embodiment and comprises a blade device (10A), a motor (20A), a magnet device (30A), a frame (40A) and a ball bearing (50A).

The second embodiment differs from the first embodiment in the following points.

The frame (40A) of the second embodiment further comprises a tube (43A). The tube (43A) comprises an inner surface, a first opening (431A) and a second opening (432A). The second opening (432A) is attached to the base (411A). The inner flange (42A) of the second embodiment is attached to the inner surface of the tube (43A) between the first opening (431A) and the second opening (432A) of the tube (43A). Preferably, the inner flange (42A) is attached to the inner surface of the tube (43A) near the first opening (431A) of the tube (43A).

Furthermore, the resilient member (412A) of the second embodiment is a resilient ring.

With reference to FIGS. 5 and 6, a third embodiment of tilt-preventing fan in accordance with the present invention is similar to the aforementioned second embodiment and comprises a blade device (10B), a motor (20B), a magnet device (30B), a frame (40B) and a ball bearing (50B).

The third embodiment differs from the second embodiment in the following points.

The receiving device (41B) of the third embodiment further comprises an adapter (414B) and an annular pad (415B). The adapter (414B) is mounted between the abrasion-resistant pad (413B) and the first end of the resilient member (412B). The annular pad (415B) mounted between the adapter (414B) and the outer rail (51B) of the ball bearing (50B).

The resilient member (412B) of the third embodiment is a spring, which is similar to that of the first embodiment.

With the aforementioned structure, the tilt-preventing fan in accordance with the present invention is capable of preventing the blade shaft from tilting with only one ball bearing. The tilt-preventing fan, which has only one ball bearing, is suitable for downsizing and needs no extra ball bearings or sleeves and thus is more commercially competitive.

Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A tilt-preventing fan comprising a blade device comprising a blade shaft comprising an outer surface; a first end; a second end; and a ring formed on the outer surface between the first end and second end; and multiple blades radially mounted between the first end and the ring or radially mounted to the first end; a motor for rotating the blade shaft mounted around the blade shaft and comprising a central hole receiving the blade shaft and comprising an inner surface; a first opening; and a second opening; a magnet device providing the motor a magnetic field and mounted around the motor; a frame holding the blade device, the motor and the magnet device and comprising a receiving device mounted into the central hole of the motor from the second opening and comprising a base comprising a first surface; a resilient member attached to the first surface of the base and comprising  a first end; and  a second end attached to the first surface of the base; and an abrasion-resistant pad attached to the first end of the resilient member and abutting to the second end of the blade shaft; and an inner flange positioned around the blade shaft between the blades and the ring; and a ball bearing holding the blade shaft and mounted between the ring and inner flange and comprising an annular outer rail pushed by the inner flange towards the ring and comprising a semicircular outer groove comprising  a first outer portion; and  a second outer portion; an annular inner rail pushed by the ring towards the inner flange and comprising a semicircular inner groove comprising  a first inner portion; and  a second inner portion; and multiple balls movably mounted between the outer groove of the outer rail and the inner groove of the inner rail.
 2. The tilt-preventing fan as claimed in claim 1, wherein the blade shaft further comprises an annular slot formed on the outer surface between the first end and second end of the blade shaft; and the ring is mounted around the annular slot.
 3. The tilt-preventing fan as claimed in claim 3, wherein the receiving device further comprises an adapter mounted between the abrasion-resistant pad and the first end of the resilient member.
 4. The tilt-preventing fan as claimed in claim 4, wherein the receiving device further comprises an annular pad mounted between the adapter and the outer rail of the ball bearing.
 5. The tilt-preventing fan as claimed in claim 1, wherein the inner flange is attached to the inner surface of the central hole between the first opening and the second opening of the central hole.
 6. The tilt-preventing fan as claimed in claim 1, wherein the frame further comprises a tube comprising an inner surface; a first opening and a second opening attached to the base; and the inner flange is attached to the inner surface of the tube between the first opening and the second opening of the tube.
 7. The tilt-preventing fan as claimed in claim 1, wherein the resilient member is a spring.
 8. The tilt-preventing fan as claimed in claim 1, wherein the resilient member is a resilient ring. 